I didn't think 5 speed boxes had overdrive. Would this be something the MoD would have added? I don't know. I'll give a spin today and see if it makes a difference at high speed. Thanks for the comments

Hello there, I've just bought a 1987 Ex Mod 110 2.5 N/A diesel. There is a switch and an LED on the gear knob, and I have no idea what it's for. When you switch the ignition key to it's 1st position (run), the LED flashes a few times then goes off. If you operate the switch it flashes a...